Question: Simplify the following expression: ${-2(2z-7)+9(-4+9z)}$
Explanation: Distribute the ${-2}$ into the first set of parentheses: $ {-2(}\gray{2z-7}{)} + 9(-4+9z) $ $ {-4z+14} + 9(-4+9z) $ Distribute the ${9}$ into the parentheses: $ -4z+14 + {9(}\gray{-4+9z}{)} $ $ -4z+14 {-36+81z} $ Rewrite the expression to group the ${z}$ terms and numeric terms: $ {-4z + 81z} + {14 - 36}$ Combine the ${z}$ terms: $ {77z} + {14 - 36}$ Combine the numeric terms: $ {77z} {-22}$ The simplified expression is $77z-22$